Scientists are studying a group of living cells under a microscope. They write down notes about the size, shape, and color of the cells as well as other traits.

Which best describes this type of investigation?

comparative, because the scientists will be making observations in order to form a hypothesis
comparative, because the scientists are measuring dependent and independent variables
descriptive, because the scientists are using independent variables to test a hypothesis
descriptive, because the scientists are writing down observations but not making comparisons